西藏荣那河中荣那矿体天然污水的地球化学演化与生态响应

发布时间：2018-06-27 12:39

本文选题：西藏 + 荣那铜矿　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：西藏是我国未来重要的铜矿资源接替基地,其矿床主要分布于内流水域,目前尚缺乏相应地区的矿山污染规律与风险的研究。荣那矿床是西藏多龙矿集区的一个超大型斑岩铜矿体。本文在前人工作的基础上,测定了水体、沉积物、阶地土壤以及植被重金属含量,对重金属含量变化及污染程度进行了初步分析;通过原位实验测定了若干重金属在河水与沉积物之间的动态平衡;同时对矿床开发潜在污染风险进行了评价。获得如下结论:(1)矿体污水的注入导致河水理化因子、河水与沉积物重金属含量发生剧变。河水的pH与ORP先下降,然后随污水汇入距离增加缓慢上升,SO_4~(2-)含量先上升后下降。污水中Cu、Zn、Fe、Mn、Co、Ni含量分别为上游河水的1137、118、1591、119、104、17倍,Cu、Zn、Mn超过铜镍钴工业污染排放标准4.54、1.52、1.61倍。地积累指数表明污染河段沉积物中Cu为极严重污染,并对河水造成潜在二次污染隐患。一级阶地中Cu为强度污染。(2)正常情况下荣那河地表流程仅30km,然后渗漏进入地下;仅在洪水期,河流流程延长至55km注入到别错。别错沉积物重金属含量与荣那河存在显著差异,而与西藏地区其它18个大型湖泊无差异,其沉积物受到污水影响很小。(3)未受污水影响的波龙河、和荣那河上游河水重金属含量甚微,符合源头水标准;说明岩体的正常风化不会对地表水和沉积物造成污染。(4)荣那河生态系统受损严重。整个污染河段浮游动物和底栖动物消失;浮游植物趋于繁盛,平均密度比受损前高出20倍。在污染段共检出蓝藻门5种,硅藻门23种,绿藻门2种。色球藻(Chroococcus sp.)是污染河段代表性物种。相关性分析表明,生物密度与pH表现为正相关关系,与重金属含量为负相关关系。(5)重金属离子原位实验表明,Mn在沉积物与河水之间的平衡浓度为484μg/g(R5站位)。其它实验元素动态平衡点接近于实验浓度下限,无法取得可信结果,建议开展进一步工作。
[Abstract]:Tibet is an important copper mine resource replacement base in the future in China. Its deposits are mainly distributed in the inland waters. At present, there is a lack of research on mine pollution law and risk in the corresponding areas. The Rongna deposit is a very large porphyry copper deposit in the Dulong ore concentration area, Tibet. Based on the previous work, the contents of heavy metals in water body, sediment, terrace soil and vegetation were measured, and the change of heavy metal content and the degree of pollution were analyzed. The dynamic equilibrium of some heavy metals between river water and sediment was determined by in-situ experiments, and the potential pollution risk of ore deposit development was evaluated. The main conclusions are as follows: (1) the injection of ore body sewage resulted in great changes in the physical and chemical factors of river water and heavy metal contents in river and sediment. The pH and ORP of the river water first decreased and then increased slowly with the increase of the sewage inflow distance. The content of SO42- increased first and then decreased. The content of Cu ~ (2 +) Zn ~ (2 +) Fe ~ (2 +) mn ~ (2 +) ~ (2 +) in waste water is 1137 ~ 1187 ~ 1 1591U ~ (1 19) ~ (10 ~ 4) ~ (17) times that of the upstream river water. The Cu ~ (2 +) Zn ~ (2 +) mn is 1.61 times higher than the discharge standard of copper, nickel and cobalt industrial pollution. The accumulation index indicates that Cu in the polluted river sediment is a serious pollution and causes potential secondary pollution hidden danger to the river water. (2) under normal conditions, the surface flow of the Rongna River is only 30km, and then leaks into the ground, and only during the flood period, the river flow extends to 55km injection to the fault. There were significant differences between the heavy metal contents in the sediments and the Jona River, but there was no difference with the other 18 large lakes in Tibet. The sediments of the sediments were very little affected by sewage. (3) the Bolong River, which was not affected by the sewage, The content of heavy metals in the upper reaches of the river is very low, which conforms to the standard of source water, which indicates that the normal weathering of rock mass will not cause pollution to surface water and sediment. (4) the ecosystem of Rongna River is seriously damaged. Zooplankton and zoobenthos disappeared in the whole polluted reach, and phytoplankton tended to flourish, the average density of phytoplankton was 20 times higher than that before damage. A total of 5 species of cyanobacteria, 23 species of diatom and 2 species of Chlorophyta were detected in the polluted section. Chroococcus sp. It is a representative species of polluted river. Correlation analysis showed that the biological density was positively correlated with pH and negatively correlated with heavy metal content. (5) in situ experiments of heavy metal ions showed that the equilibrium concentration of mn between sediment and river was 484 渭 g / g (R5 station). The dynamic equilibrium point of other experimental elements is close to the lower limit of experimental concentration and can not obtain credible results. It is suggested that further work be carried out.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X753

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